Arthur Fleck, 34 years old, adopted son of Penny Fleck. He suffers Post-traumatic stress disorder and Pseudobulbar affect which makes him laugh uncontrollably at times which may or may not match the atmosphere, and the mood of the people. He was physically abused back at his childhood, and the trauma has caused him to lose his memories about his childhood and caused his laughing disorder. Other than his dark past, he is very soft and just want to be loved. 